This invention relates broadly to the art of connecting tubing.
More particularly the invention relates to metal members having a memory to a predetermined shape for use in square tubular furniture members for the purpose of connecting the same.
Several inventions are present for joining tubes. Moryl, U.S. Pat. No. 4,531,870 shows a four sided locking mechanism for use with square tubes.
Moryl describes an invention having a socket with a collar to provide for identical radial tabs off set by 90 degrees.
The ends of the radial tabs are fitted within a square hole (the right angle dihedon shape).
This four sided figure lies above a rounded portion and pins. When in place the sides which deform to hold the collar in place on the cylindrical socket.
The purpose of the four tabs in Moryl is different from the purpose of the tabs in the instant invention. The purpose of citing this prior art is that it visibly shows wings in a securing object which has some similarity in appearance to the wings disclosed in present invention.
The use of pins in Moryl is only shown because those pins do not function and are not defined in a similar fashion to the wings in the present invention.
Instead they are pointed out because they show how different techniques are used in prior art in order distinguish them from the technique in the present invention.
The invention alleviates the need for the use of the pins by having biting surfaces which greatly simplifies the invention. The present invention also uses arms for actual attachments as opposed to being for the purpose of 45 degree rotation.
Moryl shows the radial tabs designed to rotate within four longitudinal windows, which actually teaches away from the disclosed invention with this specification.
The design utilized for accomplishing the present invention which is present in the prior art utilizes a plurality of extending legs such as those shown in Martelli, U.S. Pat. No. 4,810,144.
Martelli shows a plurality of angular legs.
Also sharp edges of the legs are known which dig aggressively into the inner walls of the tube to resist withdraw.
Pleickhardt, U.S. Pat. No. 4,518,293 shows a tube connecter which incorporates the spaced segments referred to as legs as the cutting edge of at least some of the legs in order to help it resist turning motion. In addition, Pleickhardt describes a radial slit, which is presumably to allow the disk to absorb some of the compression when the disk is inserted.
U.S. Pat. Nos. 4,810,144 Martelli et al. shows a tube connector with springs 28 and 30. Also it shows square tubing 22A in FIG. 2.
U.S. Pat. Nos. 3,864,051 Reid et al. discloses a connector for square tubular member. Note the spherical radius of spring 7 in FIG. 3.
The Reid patent does not obtain a spherical radius, but instead defines a curved portion which, if sufficiently compressed, would join two edges of a space formed by section 7 & 8 in order to define a closed semicircular member.
The flats of the spring are not in the corners of the tubular member, however.
U.S. Pat. Nos. 2,618,009 Tinnerman; 2,654,620 Tinnerman; and 4,518,293 Pleickhardt show springs inside of a tube.
U.S. Pat. Nos. 3,320,846 Orain and 4,604,014 Frano show springs inside of a bore. None of these are similar prior art.
U.S. Pat. No. 4,531,870 Moryl et al. shows tabs in the corners of a square hole 2. The tabs are not of a spherical radius and do not relate directly to the invention disclosed herein as described in more detail below.